While research on homeless youth is increasing, there is a dearth of information regarding effective interventions for these youth. This is of significant concern because studies indicate that 70-95% report problem alcohol or drug use and 66% to 89% of homeless youth have a mental health disorder (Cauce et al., 2004). Suicide is the leading cause of death with up to 68% of youth reporting a lifetime suicide attempt (Rotheram-Borus & Milburn, 2004; Yoder, Whitbeck, & Hoyt, 2010). Among those who have attempted, an average of 6.2 attempts is reported. In addition, lifetime suicide ideation rates have ranged from 14% to 66.5% (Kingree et al., 2001; Merscham et al., 2010; Yoder, Whitbeck, & Hoyt, 2010). Some predictors of suicide among homeless youth have been identified. These include substance use, childhood physical and sexual abuse, victimization experiences while living on the streets, and psychological functioning, including depression, hopelessness, distress tolerance, impulse control, social support, and problem solving. This study uses general cognitive theory (Beck, 1967), complemented with concepts from two suicide specific theoretical models, to guide our intervention and conceptual change model. Consonant with the pilot R34 announcement, this study's goal is to pilot test an intervention that has previously demonstrated feasibility and promise with adolescent suicide attempters (Brent et al., 2009; Stanley et al., 2009) and efficacy with a low-income sample of adults, The Cognitive Therapy Intervention for Suicide Attempters (Brown et al., 2005). One-hundred fifty homeless youth with recent severe suicide ideation will be randomly assigned to the experimental cognitive therapy for suicide prevention (CTSP) + services as usual (SAU) (n=75) or to SAU alone (n=75). SAU includes those services normally offered through a local drop-in center. Follow-up assessments will be conducted at 3, 6, and 9-months post-baseline. It is hypothesized that youth receiving CTSP+SAU will show greater reductions in suicide ideation (primary outcome), substance use and depressive symptoms (secondary outcomes) over time compared to SAU alone. Furthermore, theoretically-derived mediators will be tested to shed light on mechanisms associated with change. The data from this study will be used to determine the initial efficacy of this promising intervention, and determine whether findings warrant a broader scale effectiveness trial. Ultimately, attention towards reducing suicide risk among these youth has the potential to reduce premature mortality, hospitalization and loss of human capital in a very high risk population of youth.